Apparatus for continuous metal casting



Dec. 9, 1969 J. DUMONT-FILLON APPARATUS FOR CONTINUOUS METAL CASTING 3 Sheets-Sheet 1 Filed April 4. 1967 Dec. 9, 1969 J DUMONT-FlLLON 3,482,620

APPARATUS FOR CONTINUOUS METAL CASTING Filed April 4, 1967 I 3 Sheets-Sheet 2 5 Fig.3

9, 1969 J. DUMONT'FILLON 3,432,520

APPARATUS FOR CONTINUOUS METAL CASTING Filed April 4, 1967 5 Sheets-Sheet 5 awdzw fiy fi n United States Patent C) 3,482,620 APPARATUS FOR CONTINUOUS METAL CASTING Jacques Dumont-Fillon, Metz-Queuleu, Moselle, France, assignor to Institut de Recherches de la Siderurgie Francaise, Saint-Germain-en-Laye, France Filed Apr. 4, 1967, Ser. No. 628,444 Claims priority, application France, Apr. 8, 1966,

Int. Cl. 1522a 11/06 US. Cl. 164278 14 Claims ABSTRACT OF THE DISCLOSURE An apparatus for continuous metal casting including a flow mold having opposite open ends and a cross section in form of a right quadrangle in which at least two opposite walls of the flow mold are formed by a pair of endless flexible bands and rollers supporting the bands movable in longitudinal direction, and pressure means cooperating with the flexible bands for maintaining the face of each band over the whole length of the mold in contact with the metal poured into one of the open ends of the mold despite shrinking of the metal during its solidification in the mold.

Background of the invention The present invention relates to an apparatus for continuous metal casting and including a flow mold having opposite open ends in which the liquid metal is continuously poured into one of the open ends of the mold, which has a length suflicient to assure solidification of the metal as it passes through the mold, so that the solidified metal may be withdrawn in a continuous manner from the other Open end of the mold. More specifically, the apparatus of the present invention relates to a flow mold in which the walls of the mold are movable in direction of the metal passing therethrough.

Apparatus for continuous metal casting are known in which the metal is continuously cast in a flow mold formed by movable bands or chains. In these known flow molds, the spacing between opposite walls of the mold is fixed so that during shrinking of the metal which solidifies while passing through the mold, a space is formed between the inner surfaces of the mold walls and the surface of the solidifying metal. These air spaces of small heat conductivity considerably retard the cooling of the metal. Due to this fact a reheating of the outer rather thin crust of the solidifying metal may occur, in which case a piercing of this crust is inevitable.

It is one object of the present invention to provide in an apparatus for continuous metal casting a flow mold which overcomes the disadvantages of such flow molds known in the art.

It is an additional object of the present invention to provide in an apparatus for continuous metal casting a fiow mold which is constructed in such a manner that the inner surfaces of the flow mold will be maintained in contact with the solidifying metal passing therethrough despite the shrinkage of the metal as it solidifies.

Summary of the invention With these objects in view, the apparatus for continuous metal casting according to the present invention mainly comprises a flow mold having opposite open ends and a cross section in the form of a right quadrangle and comprising a first pair of opposite spaced walls formed by a pair of endless flexible bands and rollers supporting and guiding said bands movable in longitudinal direction, and a second pair of spaced opposite walls extending substantially normal to the first-mentioned pair of walls and having a width greater than the spacing between the first pair of walls and being spaced from each other a distance substantially equal to the width of the aforementioned bands so that the bands engage with side edges thereof the walls of the second pair of walls so as to be movable in longitudinal and transverse direction with respect to the latter, means for feeding liquid metal into one of the open ends of the mold, withdrawal means arranged adjacent the other open end for continuously withdrawing the metal after it has solidified in the mold through the other open end thereof, and pressure means cooperating with the flexible bands for maintaining a face of each band over the whole length of the mold in contact with the metal, despite the shrinkage thereof during solidification.

The apparatus according to the present invention may have in addition the following characteristics combined with the characteristics set forth above:

(a) The second pair of walls of the flow mold may be constituted by fixed walls;

(b) The second pair of walls may also be constituted by flexible endless bands supported and guided by rollers and adapted to move at the same speed as the bands which form the first pair of walls;

(0) The pressure means may comprise movable frames and carrying rollers engaging the flexible bands on the faces thereof opposite the faces which are in contact with the metal passing through the flow mold and biasing means biased in the direction to maintain the bands in contact with the metal passing through the flow mold;

(d) The pressure means may be constituted by a plurality of independent rolls engaging the bands on the face thereof opposite to the face which is in contact with the metal and each provided with biasing means biasing the roller towards the axis of the mold so as to maintain the bands in contact with the metal;

(e) The biasing means according to (c) or ((1) may be constituted by springs;

(f) The biasing means according to (c) or (d) may be constituted by fluid-operated jacks;

(g) The peripheral surfaces of the rollers which guide the band may be provided with spaced projections abutting with the extremities thereof against the bands.

The endless bands a e metal bands the ends of which are fixed by welding or otherwise to each other, for instance in the manner of a transmission belt.

Due to the fact that the longitudinal edges of the bands forming the first pair of walls may slide on the surfaces of the second pair of walls, the pressure means cooperating with the bands will assure that the latter will remain continuously in contact with the metal passing through the mold. Therefore, while the metal solidifies and consequently shrinks, the pressure means permit the bands to follow exactly the profile of the solidifying metal despite the shrinkage thereof, and this constitutes one of the aims and advantages of the present invention.

From this construction follows also that the cooling of the solidifying metal will be very rapid, which thus permits a pouring speed of the metal .much greater than in similar apparatus known in the art, and in consequence an increased output is obtained with the apparatus according to the present invention. An additional advantage of the apparatus according to the present invention is that the cooling of the metal passing through the mold is progres sive and continuous so that the risk of formation of cracks in the produced continuous ingot is prevented.

The longitudinal axis of the flow mold of the apparatus according to the present invention may be arranged vertically, horizontally or inclined at any angle to the horizontal.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

Brief description of the drawing Description of the preferred embodiments Referring now to the drawing, and more specifically to FIGS. 1 and 2 of the same, it will be seen that the apparatus according to the present invention may comprise a vertically arranged flow mold having opposite open ends, and as can be best seen from FIG. 2, a substantially rectangular cross section. The flow mold may be formed by a first pair of spaced opposite walls formed by a pair of endless flexible bands of sheet metal and a second pair of spaced opposite walls formed by two fixed blocks 2 and 2a, preferably of copper and cooled by cooling water circulated through the bores 3 and 3a formed through the blocks. The second pair of 'walls formed by the blocks 2 and 2a extend substantially normal to the first pair of walls and they have a width greater than the spacing between the first pair of walls and are spaced from each other distance substantially equal to the width of the bands 1 and 1a so that the longitudinal edges of the bands may slide in longitudinal and transverse direction on the surfaces of the blocks 2 and 2a which face each other. The apparatus includes further means for feeding liquid metal 4 into the upper open end of the flow mold, and these means may comprise a receptacle 5 having an outlet opening arranged above the flow mold substantially aligned with the axis thereof. The speed of discharge of the molten metal 4 from the receptacle 5 is regulated in a manner known per se by the operator, for example by maintaining a constant level 6 of the metal in the receptacle, and the liquid metal is fed into the receptacle in a manner known per se not forming part of the present invention.

The bands 1 and 1a welded at their movement to each other are respectively mounted for movement in longitudinal direction on guide rollers 7 and 8, respectively 7a and 8a.

The two bands will evidently move together with the metal passing through the mold at the same speed. The guide rollers 7 and 8 and the guide rollers 7a and 8a are respectively supported on two fixed frames 9 and 9a, which in turn are mounted on fixed support means not shown in the drawing. The frames 9 and 9a support in turn two movable frames 10 and 10a respectively tiltable about fixed axes 11 and 11a. The movable frame 10 carries a plurality of small pressure rollers 12, 13 and 14 spaced from each other and turnable about axes substantially parallel to the axis 11, and at its lower end a pressure and guide roller and in the same manner the movable frame 10a carries small pressure rollers 12a, 13a, and 14a and, at its lower end, a pressure and guide roller 15a. Fluid-operated jack means 16 and 16a are respectively mounted on the fixed frames 9 and 9a and connected to the movable frames 10 and 10a so that the latter may be turned about their axes to press thereby the pressure rollers 12, 13, 14 and 12a, 13a, 14a as well as the guide and pressure rollers 15 and 15a, respectively, against the bands 1 and 1a which are thus applied against the solidifying metal 17 passing through the mold and wh h p rmits the bands 1 and lg to QI QW h m ta during its shrinkage and to thus remain in contact with the large faces of the solidifying metal ingot. The small pressure rollers are provided on the peripheral surface thereof with a plurality of rigid projections 18 arranged staggered with respect to each other and the extremity of which form a sort of cylindrical brush on which the bands circulate. A plurality of nozzles 19 permits to cool the bands 1 and 1a by means of water jets 20, and due to the presence of the projections 18, the sum of the points of contacts of which with the bands cover only a very small area, the cooling jets will wet the bands even at the portions thereof between the bands and the small pres sure rollers.

The apparatus includes further withdrawal means arranged adjacent the bottom end of the flow mold, which withdrawal means may be constituted by a pair of withdrawal rollers 21 engaging the solidified metal emanating from the mold and which are driven by motors not shown in the drawing for continuously withdrawing the solidified metal from the mold.

FIGS. 3, 4 and 5 illustrate a second embodiment of a fiow mold according to the present invention in which the flow mold is formed by four movable bands and in which the bands forming the first pair of opposite walls are pressed against the solidifying metal by rollers mounted movable independent from each other and each provided with springs to press the rollers toward the axis of the flow mold.

Elements in FIGS. 35 which are the same as elements in FIGS. 1 and 2 are referred to with the same reference numerals.

The bands 1 and 1a are movable on rollers 7, 8 respectively 7a, 8a, which in turn are supported turnable about parallel axes on the frames 22 and 22a. Arms 23, 24, 25 and 23a, 24a, 25a are respectively fixedly connected to the frames 22 and 22a and respectively support the axes of small pressure rollers 26, 27, 28 and 26a, 27a, 280 at opposite ends thereof and the aforementioned small pressure rollers are pressed respectively against the bands 1 and In by means of individual springs 29, 30, 31 and 29a, 30a, 31a. The axes of the guide and pressure rollers 32 and 32a are in the same manner supported on arms 33 and 33a respectively flxed to and projecting from the frames 22 and 22a. The rollers 32 and 32a which are arranged in the region of the bottom end of the flow mold are pressed respectively against the bands 1 and 1a by springs 34 and 34a so that the rollers 32 and 32a form also pressure rollers. This arrangement in which the rollers are pressed individually against the respective bands has the advantage that the bands may exactly follow the shrinkage of the metal even if the shinkage occurs in a nonuniform manner. Uniform shrinkage is to be understood as a shrinkage in which the outer faces of the metal solidifying in the mold would form a pyramid frustum.

The second pair of walls of the flow mold are in this case formed by the endless bands 35 and 35a movably supported on rollers 36, 37, 38 and 36a, 37a, 38a, respectively, as best shown in FIG. 5. The aforementioned rollers are turnably supported on fixed frames 39 and 39a, respectively, which are provided respectively with fixed arms 40, 41, 42 and 40a, 41a, 42a supporting the extremities of the axis of small rollers 43, 44, 45 and 43a, 44a, 45:: which permit the bands 35 and 35a to remain in constant contact with the longitudinal edgesof the bands 1 and In. As clearly shown in FIG. 4, the width of the bands 35 and 35a is greater than the distance between the band 1 and 1a. a

The small rollers 43-45 and 43a45a are again provided with small projections on the peripheral surface thereof and the bands 35 and 35a are likewise cooled by water jets sprayed against the bands from the nozzles 47.

The operation of the two embodiments above-described during casting of steel is as follows: at the start of the operation, the pressure means are reduced inoperative and a steel bloclg having a cross section slightly smaller than the open cross section of the mold is inserted into the latter with the lower end of the block arranged between the withdrawal rollers 21 and 21a. The pressure means are then released so that the steel block is held in place. The upper face of the steel block is then covered with a layer of asbestos and with granulated steel. Subsequently thereto, molten steel is poured into the upper portion of the mold where it progressively solidifies in contact with the cooled walls thereof. Then the motors which turn the withdrawal rollers 21 and 21a are started and the metal which is continuously poured into the mold slowly fills the latter while the steel block is withdrawn by means of the withdrawal rollers. At the same time, bands 1 and 1a, and in the embodiment shown in FIGS. 3-5, also the bands 35 and 35a, are entrained by the downward movement of the steel block and subsequently thereto by the solidified metal which is in turn gripped and entrained by the withdrawal rollers.

In the two above-described embodiments, the movable bands arranged to follow the solidifying metal during its shrinkage are applied onto the large faces of the solidifying metal. While this disposition is most favorable from a thermal viewpoint, it is to be understood that the invention can also be carried out with the bands applied to the small side faces of the metal ingot to be formed. The invention may be used not only for continuous casting of steel, but likewise for the continuous casting of other metals such as lead, copper, aluminum, antimony, various alloys, etc.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of apparatus for continuous casting of metal differing from the types described above.

While the invention has been illustrated and described as embodied in apparatus for continuous metal casting and including a flow mold having a pair of opposite walls formed by endless flexible and movable metal bands arranged to remain in contact with the metal during shrinkage thereof, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. An apparatus for continuous metal casting comprising, in combination, a flow mold having opposite ends and an open cross section in the form of a right quadrangle and comprising a first pair of spaced opposite walls formed by a pair of endless flexible bands and roller means supporting and guiding the bands movable in longitudinal direction, and a second pair of spa ed opposite walls having faces defining part of said open cross section of said flow mold, said faces extending substantially normal to said first pair of opposite walls defined by said pair of endless bands and having a width greater than the spacing between said first pair of walls and being spaced from each other a distance substantially equal to the width of said bands so that said bands engage with side edges thereof said faces of the walls of said second pair of walls and are movable with respect thereto in longitudinal and in transverse direction; means for feeding liquid metal into one of said open ends of said flow mold; withdrawal means adjacent to the other open end for continuously withdrawing the metal, after it has solidified in said mold, through said other open end; and moving means cooperating with said flexible bands for moving the same at least partly and to different extents against each other, when required, for maintaining a face of each band over the Whole length of the mold substantially in contact with the metal passing therethrough despite the shrinkage of the metal during solidification while maintaining the edges of said bands in contact with said faces of the walls of said second pair of walls.

2. An apparatus as defined in claim 1, wherein the walls of said second pair of walls are fixed walls.

3. An apparatus as defined in claim 1, wherein the walls of said second pair of walls are likewise formed by endless flexible bands and rollers supporting the same movable in longitudinal direction at the same speed as said flexible bands forming said first pair of walls.

4. An apparatus as defined in claim 1, wherein said moving means comprise spring means.

5. An apparatus as defined in claim 1, wherein said moving means comprise fluid-operated jack means.

6. Apparatus as defined in claim 1, wherein said moving means for each band comprises a plurality of rollers one of which is located in the region of said other open end of said mold, supporting means supporting said one roller movable toward and away from the axis of said mold, and biasing means constructed and arranged for biasing said one roller towards the mold axis.

7. An apparatus as defined in claim 6, wherein said biasing means comprise spring means.

8. An apparatus as defined in claim 6, wherein said biasing means comprise fluid-operated jack means,

9. An apparatus as defined in claim 6, wherein said supporting means comprise a movable frame, and including a plurality of additional pressure rollers turnably carried by said movable frame spaced from each other in longitudinal direction of said band and engaging the latter on a face thereof opposite the face which is in contact with the metal.

10. An apparatus as defined in claim 9, wherein said movable frame is mounted pivotable about a fixed tilting axis located in the region of said one end of said mold and extending substantially parallel to the axis of said one roller, and wherein said pressure means comprise fluid-operated jack means connected to said movable frame.

11. An apparatus as defined in claim 6, wherein said moving means further comprise a plurality of additional pressure rollers turnably carried by said support means spaced from each other in longitudinal direction of said band on the side thereof facing away from the mold axis, and each movable independent from the other toward and away from said axis, and biasing means for each additional roller and biasing the same toward the mold axis.

12. An apparatus as defined in claim 11, wherein said biasing means are spring means.

13. An apparatus as defined in claim 1, wherein at least some of said plurality of rollers are provided on the peripheral surface thereof with a plurality of projections engaging with the extremities thereof the respective band.

14. An apparatus as defined in claim 13, and including means for spraying a cooling fluid onto the surface of each band opposite the surface thereof which is in contact with the metal.

References Cited UNITED STATES PATENTS 594,583 11/1897 Wood 164-278 1,139,884 5/1915 Mellen 164279 2,904,860 9/1959 Hazelett 16487 2,978,761 4/1961 Foye et al. 164-278 3,210,812 10/1965 Berwick 164-282 FOREIGN PATENTS 519,174 12/1955 Canada.

J. SPENCER OVERHOLSER, Primary Examiner JOHN S. BROWN, Assistant Examiner 

